grinder11

iTrader: (1)

Darth, I have a question. When using thin, steel shims for optimum wipe pattern, is there a preferred steel type? I ask because I'm sure you know the reaction of dissimilar metals, i.e., steel on aluminum. Or is this a non factor with the amount of oil being pumped to the rocker? Guess that's more than 1 question!!!

Darth_V8r

iTrader: (4)

It's a non-factor. If there was water going through it would be a very big deal, but you have the dissimilar metals thing all the time in the engine right now - bearings installed in block, parts riding on bearings, steel bolt inserts in aluminum, etc. Oil is far less conductive than water. I'll use stainless shims, mainly because that's almost always what you find more commonly available.

That much said -- GROUND YOUR RADIATOR!!!! the cooling system will be quite reactive. Grounding the radiator greatly reduces the chance of building up an electric charge.

99 Black Bird T/A

iTrader: (4)

Please elaborate.

Does electric charge impact how Dex-Cool, Green, Multi-purpose or G05 react?

Best way to ground a factory plastic sided radiator?

Darth_V8r

iTrader: (4)

Basically, if the radiator is not grounded, the only electrical path to ground for the radiator is through the coolant. Pretty much any antifreeze you buy is going to turn water - even distilled water - into a reasonable conductor. If the radiator is not grounded, it can and does wind up at a different voltage than the engine via static build up, and this will eventually break the antifreeze down into a weak acid, which then conducts electricity even better, and the circle of death begins. By grounding the rad, it will be at the same electrical potential as the engine, which avoids the voltage buildup, and the resulting electrolysis of the fluid and the radiator metal. Now, we're not talking about a huge voltage. Usually something like 0.3V. Which does nothing in the short term, but over time eats away as described. It's a slow death.

As to HOW, the top lip of the plastic-sided radiator has aluminum flanges that stick up. Conveniently, there are even slotted holes in it. Run a bolt through the hole, attach ground strap, and ground other end to the top of the core support. I used pipe hangers on mine, lol. When I installed a larger radiator, I used the side flange since the new piece was all metal.

Full Disclosure: You can also look up on the internet and find equally convincing arguments to NOT ground the radiator, saying that what happens is stray current from other stuff in the car that is also grounded to the chassis finds its way into the cooling system via the radiator ground and causes the electrolysis. My belief is that there is a difference between properly grounded vehicles and improperly grounded vehicles - i.e. those that have upgraded their grounds (Big 3) vs those that have not. Electrons will always follow the easiest path back to the battery negative. If electrons are going through the radiator ground, into the cooling system, to the engine, back to the chassis, and then to the battery, then I propose the following:

1. This should not be possible, since the electrons will have gone from the chassis to the chassis, which should have no electrical potential
2. The ground from the chassis to the battery is too small

Also, in many cases, those who advise against grounding the rad ALSO tend to advise using a sacrificial anode - i.e. a small piece of aluminum ingot in the cooling system to give it aluminum to eat so that it does not eat the radiator. My opinion is if the elimination of the radiator ground fixed the problem, why would you need the sacrificial anode?

So there it is. Both sides as best as I can articulate them quickly. If you hunt around on the internet, you'll find it's a funny recurring argument a-la square ports vs cathedral ports.

ddnspider

iTrader: (26)

Sacrificial anode is good stuff, but agree its a bandaid. Fix the grounding issue first.

99 Black Bird T/A

iTrader: (4)

Darth, thank you excellent information 👏 👍

Also seems like yet another good reason to flush the cooling system and change coolant every ~ 5 years or so.

SLOW SEDAN

iTrader: (13)

The things people worry about

AwesomeAuto

I know right?
I haven't seen this much debate on coolant type since.... well, basically every time I go to Corvetteforums.

99 Black Bird T/A

iTrader: (4)

It's time to check the G05 again in my Corvette and put another electric blanket on the hood, thank you 😊

grinder11

iTrader: (1)

It always surprises me on how fussy the C5 is on grounds. You'd think that the water/coolant flowing thru the radiator would ground it, seeing as it also flows thru the engine, which has the negative ground cable from the battery bolted directly to the block. But I guess it's not good enough.......

jayyyw

So, the reason behind this post.... I ended up picking up another C6z. It has quite a bit of goodies on it and makes 644whp/600wtq according to the previous dyno. Brodix heads ported by LME, Milled to 62cc, shimmed up PAC 1209x springs, TSP roller rockers, Johnson 2110 lifters, 253/263 .666 111+5 camshaft (TSP lobes), 1-7/8 headers, ported MSD intake, ported OEM tb, and tuned on E85. It also has 3.90 gears.

My immediate concerns with the setup; TSP rockers (just not a fan), the Johnson lifters are rated for ~410# max open pressure and the PAC springs are likely in the ~520# range currently, HP peak was 6200rpm which is pretty low even with the MSD intake. The valvetrain is pretty noisy and I am attributing this to the high seat/open pressure of the PAC springs. I also believe this may be the reason for the low HP peak rpm. I have parked the car until I receive new springs to swap in there.

Plans are to change the TSP rockers and go back to stock, BTR Trinity intake, 2" headers, change the springs for some BTR .685 springs (shimmed accordingly), and a different air intake.

A little history on the current heads/cam/headers. These exact parts were on a different C6z that made 680whp on the same dyno my car was tuned on. So, I know there is potential there to get near or eclipse that number.

Goal with this car is to make over 700whp and not have to go crazy to do it. So, next step is considering a solid roller camshaft, send the heads off to get reworked, then send them to WCCH to get milled further for more compression. I've contacted Cam Motion for a LLSR camshaft. This is what I got back from them: 254/270 .69X/.68X 112.5+3. Now, I'm definitely not a cam guru but I was hoping for something with a little more duration and lift. Doesn't seem like this is very different from the current cam I am running. I even replied to them with my "concerns" and he was adamant that this cam would pick up good power over the current camshaft. I have also reached out to COMP for a traditional solid roller cam spec but have not heard back from them yet.

Darth_V8r

iTrader: (4)

hi Jay, Not sure if this will help or hurt, but I'll throw a penny into the pot on this....

My opinion is that your current cam is underperforming. I had to break it down into valve events to see what is going on:

Valve.......TSP.......LLSR
IVC.........52.5........54
EVO.......67.5.......67.5
Overlap...36.........31.5

At 52.5 IVC, your peak power should be 6500 to 6800. If it's peaking at 6200, there is a reason. If you feel comfortable, post the dyno graph. If not, I understand. Your comment about a noisy valvetrain coupled with what might be a mismatch of parts might mean you're getting some valve float. If your guess about the PAC spring pressure is correct, then it is possible the lifters are collapsing, which is costing you both lift and duration. That could also be the source of valvetrain noise. This is all internet diagnoses, and you've likely already rode this train of thought. Stock rockers at .660 lift is pushing it IMO, unless you're running lash caps to spread the wear out. Side scrubbing ahoy.

As to the cam that CM recommended, mine is 256/270-114+4, so honestly almost identical to what you were recommended, and I made 693rwhp with #3 cylinder head intake runner had a hole in it, so it was sucking in tons of oil. What you have with an IVC of 54 vs 52 will rev out higher, and power is as much about RPM as it is about torque. You got 600 rwtq, which is actually quite good. Almost happy dyno good, unless it was an engine dyno. In this case, you're not going to make more torque via a cam swap, so all your gains will have to come from RPM. I think what I expect is if you swap in the cam motion cam, you'll benefit from the increased stability, the inability to collapse the lifters, and the later IVC. You're losing a little bit of seat to seat timing, and you're losing a little bit of overlap, so it will actually drive better. My guess is your peak torque will drop just slightly due to the reduced overlap, but you'll continue to build power to about 6800 rpm and carry to 7100 before it falls off.

As to 700 rwhp -- I've only seen one sbe LS7 go over 700rwhp, and that cam was 258/272 and right at .700 lift. I don't remember the LSA. I'm sure there have been others. That's the only one I've seen. Cracking 700 rwhp is extremely difficult NA. See above on my cam, power, and that is a built 440.

I do agree your intake is not the problem. Mine peaked at 7000 rpm and it's also a msd.

You don't mention compression, but I'm guessing in the 12.1 to 12.3 range?

Likely none of that was helpful for your thought processes, but there are some thoughts at any rate.

jayyyw

This is pretty much EXACTLY what I was getting at. The high spring pressures are collapsing the lifters which is causing the low HP peak and valve train noise. There are other things that have lead me down to this train of thought. On WOT shifts, the car "stumbles" a little. My previous setup did something similar and it was floating the valves. It goes progressively worse until I ended up bending all 8 exhaust valves in the burn out box at the track. Also, the dyno pull was only made to about 7200rpm. The rev limit in the tune is set to 7700rpm. I tried to do a pull passed 7000rpms and it felt like I hit a brick wall. So, I will be changing the springs out as soon as possible. As for the stock rockers. I know it's not ideal but they won't be on too long, as I will be gathering the parts to do the solid roller camshaft in the mean time. I just want to drive the car and enjoy it a bit before I tear it down.

I am also a bit skeptical on the 600wtq number. The car does hit hard from a 60mph punch in 2nd gear. It is a hub dyno, so the numbers could be slightly exaggerated. I actually miss typed the cam specs that CM sent me. Its actually 254/270 112.5. According to the calculator on Wallace racing, it's showing overlap of 37 degrees. Also the valve events changed a little:
IVO is 17.5 ° BTDC ( - indicates ATDC)
IVC is 56.5 ° ABDC
EVO is 70.5 ° BBDC
EVC is 19.5 ° ATDC ( - indicates BTDC)
Overlap is 37 °

How does this change your speculations? IVC is 2.5 degrees higher, so would that mean it should even peak higher? I'm okay with losing some torque to gain RPM.

If you're talking about the Monte Carlo with the LS7 that made 700whp, I know who you are talking about and I also haven't seen anyone else actually do it. Although, like you, I am sure there might be others out there.

My compression is in that range, yes. 12.2:1 I'm sure. I spoke to WCCH and was told they should be able to get, at least, another point of compression out of the heads with an angle mill. So that will be the route I go when I pull the heads off.

I appreciate you taking the time to respond. You pretty much hit the nail on the head with your initial speculations. I'd appreciate any further knowledge you're willing to share. From purely a numbers perspective, I like the specs on your cam -.-

Darth_V8r

iTrader: (4)

One thing to figure into our maths -- is 254/270 the solid cam spec or the hydraulic equivalent? When I specify a cam, I start with hydraulic events and then I add five degrees duration, because your lash will grow as the engine warms up on an aluminum block. So I look at it like it's a 249/265. So for reference, my cam at 256/270 I mentally treat it as 251/265. So that's where I came up with 54 degrees IVC.

jayyyw

I see what you’re saying. I’m pretty sure it’s the solid cam spec.

Fishmasterdan

434 solid roller from Cam motion and I think its a little light if you can get enough solid roller springs
This is for a LME brodix ls7 head 61cc.

Mid Lash Solid Roller:
261/277 Duration @ .050''
112 LSA, 109 ICL (112+3)
.465''/.455'' Lobe Lift
.837''/.819'' Lift with 1.8 ratio rockers

jayyyw

Some massive lift there. How much power does it make?